This invention relates to a new dynamometer apparatus and specifically to a dynamometer for measuring the tension which exists within the bridle of a pumpjack unit. The tension within a string of sucker rod changes during each pumping cycle of a pumpjack unit associated with a pumpjack apparatus in a manner known to those skilled in the art. Dynamometers of the prior art are usually very expensive, and for this reason, the dynamometer is carried from one well to another, where it is removably connected by one means or another in such a manner that a sensing unit associated therewith measures the tension effected within the rod string. The value of the tension is usually recorded to provide a record of well performance.
Usually the pumpjack unit must be shut down and parts thereof repositioned so that the sensing unit can be interposed in such a manner that the measuring or sensing unit must carry the entire weight of the sucker rod string. This expedient enables the sensing unit to directly measure the rod string tension during each pumping cycle of the pump assembly.
Considerable loss in production is occasioned by the down time required in the installation and removal of the dynamometer respective to the sucker rod string. Moreover, the prolonged down time of the pumpjack unit necessitates the presence of a technician for another prolonged interval of time, because he usually is interested in analyzing the well characteristics until a "pump-off condition" is encountered. Accordingly, dynamometers of the prior art are not only expensive in initial cost, but the repeated use thereof is also expensive, because of the technician's time, as well as the loss of production.
Therefore, it would be desirable to have made available a dynamometer which is rugged in design, simple in operation, low in initial cost, and which can be rapidly attached to the pumpjack unit in such a manner that very little loss in production occurs. Furthermore, the time required for analyzing the well is considerably minimized.